To the original question, scholars believe dinosaurs are mentioned multiple times in the old testament. The old testament is a difficult book to read and lots of people tend to make assumptions one way or the other. Job 38:4 "Where were you when I laid the foundations of the earth?" Every age has argued over the existence of cities, cultures, customs not our own. Instead of leveling accusations, look at what you are presented with.
Here's the behemoth: Job 40:15-24
"15 Behold now behemoth, which I made with thee; he eateth grass as an ox. 16 Lo now, his strength is in his loins, and his force is in the navel of his belly. 17 He moveth his tail like a cedar: the sinews of his stones are wrapped together. 18 His bones are as strong pieces of brass; his bones are like bars of iron. 19 He is the chief of the ways of God: he that made him can make his sword to approach unto him. 20 Surely the mountains bring him forth food, where all the beasts of the field play. 21 He lieth under the shady trees, in the covert of the reed, and fens. 22 The shady trees cover him with their shadow; the willows of the brook compass him about. 23 Behold, he drinketh up a river, and hasteth not: he trusteth that he can draw up Jordan into his mouth. 24 He taketh it with his eyes: his nose pierceth through snares."
Tanniyn-mentioned 28 times in the bible orginally translated as "dragon", but is also translated “serpent,” “sea monster,” “dinosaur,” “great creature,” and “reptile.”
Leviathan-Leviathan has the following attributes according to Job chapter 41, Psalm 104:25,26 and Isaiah 27:1. This is only a partial listing—just enough to make the point. The Leviathan is one of the most mysterious animals mentioned in the bible, a sea creature that breathes fire.
1. Isaiah 27:1: "In that day the Lord with his sore and great and strong sword shall punish leviathan the piercing serpent, even leviathan that crooked serpent; and he shall slay the dragon that is in the sea."
2. Psalms 74:14: "Thou didst crush the heads of the Leviathan, thou didst give him for food to the desert people."
3. Psalms 104:25,26: "O Lord, how manifold thy works, in wisdom you have created them all. So is this great and wide sea... there go the ships and the Leviathan which you have created to play therein" (AV);
4. Book of Job 3:8 "Lo let the night be solitary, let no joyful cry be heard in it. Let them curse it who curse the day who are ready to awake the Leviathan";
5. Book of Job 41:1-34: "Can you draw out a Leviathan with a hook or press down its tongue with a cord? Canst thou put a hook into his nose? or bore his jaw through with a bridle ring? Will he make many supplications to thee? Will he speak soft words to thee? Will he make a covenant with thee? To take him for thy servant forever? Will thou play with him as with a bird? Or wilt thou bind him for thy girls? Will the tradesmen heap up payment for him?... Lay thy hand upon him, thou will no more think of fighting. Behold the hope of him is in vain, shall not one be cast down even at the sight of him? None is so fierce that dare stir him up. who then is able to stand before me?...Who can open the doors of his face? His teeth are terrible round about. His scales are his pride, shut up together as with a close seal. One is near to the another, that no air can come between them. They are joined one to another, they stick together, that they cannot be sundered. By his [sneezing] a light doth shine, and his eyes are like the eyelids of morning. Out of his mouth go burning lamps, and sparks of fire leap out. Out of his nostrils goeth smoke, as out of a seething pot or caldron. His breath kindleth coals, and a flame goeth out of his mouth....His heart is as firm as a stone; yea, as hard as a piece of the nether millstone....He esteemeth iron as straw, and brass as rotten wood. The arrow cannot make him flee: slingstones are turned with him into stubble....He maketh the deep to boil like a pot....he is a king over all the children of pride."
Unicorn/One-Horned Beast-The "unicorn," mentioned nine times in the KJV Bible, is the Hebrew word "Re-em." The Septuagint (Greek translation of the Old Testament) translated it "Monokeros" (one-horn) which was used in Bibles until the 19th century when Akkadian and Ugaritic records were found that mentioned the "Re-em" being hunted like a wild ox. However, their early pictograph for the "Re-em" shows an animal head with three horns, like a Triceratops. In Psalm 92:10 the "Re-em" has but one horn, while the language or Deuteronomy 33:17 implies two horns. Although most commentators and modern versions translate it as a bull or rhino, some have theorized that "Re-em" might be a Monoclonious (single horned dinosaur like Triceratops). In Job 39:9-12 God asks, "Will the unicorn be willing to serve you, or abide by your crib? Can you bind the unicorn with his band in the furrow? or will he harrow the valleys after you? Wilt you trust him, because his strength is great?" This passage shows that the unicorn, whatever it was, could not be tamed to be used in farming, as could an ox. In his classic work Naturalis Historia the first century author Pliny the Elder described "an exceedingly wild beast called the Monoceros [one-horned]. ...It makes a deep lowing noise, and one black horn two cubits long projects from the middle of its forehead." He describes it as like an elephant in length, but with much shorter legs. Other classical authors like Aelian, Oppian, and Martial also mention a "nose-horn" creature (a "Rinokeros"😉. Some claim that the "Rinokeros" sharpens his horn on a rock and utilizes it in fighting elephants. This is the root word from which we get the modern name rhinoceros. But a rhino does not stab with its horn, which is actually composed of keratin (hair). The correlation between the classical authors and some modern cryptozoological reports is striking. Dr. Roy Mackal’s explorations in the Congo brought back reports of a rare, single-horned animal called "Emela-ntouka" or "killer of elephants." In a recent expedition, pygmies in Cameroon identified the horned creature (there called "Ngoubou"😉 with a Ceratopsian dinosaur and claimed it could sport from one to four horns. Indeed, modern researchers believe that the ceratopsian dinosaurs likely did use their great horn for combat (Dodson, Peter, The Horned Dinosaurs:A Natural History, 1996, p.123.)